This invention concerns through-roof fittings for seamed metal roofs which are anchored to underlying roof board or sheathing and rafters for sliding along the roof surface as the roofing materials expand and contract.
Sheet material roofs such as metal roofs with standing seams have gained popularity and have become widely used in expensive homes and buildings.
The success of standing seam sheet metal roofs in protecting buildings can be seen in old farmhouses, for example, in which the structures are still intact because of the successful rain barriers formed by the standing seam metal roofs.
One of the attributes of a sheet metal roof is that it is capable of moving on the underlying roof sheathing as the metal contracts or expands with severe temperature changes. The expansion and contraction of the roof when unfettered encourages the long life of the roof because buckling and lifting is avoided.
When fixed pipes protrude from roofs, such as stacks which vent sewer lines, the roofing sheets must be sealed to the fixed stack. That sometimes causes the roofing sheets to be anchored in an undesired location on the roof which promotes buckling or tearing upon expansion or contraction. Such vents are often sealed to a roofing sheet by a bituminous substance such as roofing tar or by rubber grommets, which additionally may be tarred. The stacks may be sealed to the roof by slitting an overlying tin sheet, placing the slit over the stack and nailing the tin sheet to the roof sheathing or rafters below, and then sealing that sheet to the stack. That causes unsightly buckling and unintended movement of the roofing sheets upon the roof. Moreover, the penetration of the roof sheathing by nails causes additional breaks in the security of the roof, allowing different channels for the entry of water to damage the underlying sheathing and roof.
Needs have long existed for through-roof fittings which seal sheet roofs, such as standing seam metal roofs, without destroying the roof or the appearance of the roof or the watertight sealing of the roof.